1. Field of the Invention
The present invention relates to an alumina particle composite, a method of manufacturing the alumina particle composite, a resin composition and a method of manufacturing the resin composition.
2. Description of the Related Art
Transparent resin applicable as an alternative of inorganic glass includes acrylic resin, polycarbonate resin, polyester resin, styrene resin, epoxy resin, and the like. Among automotive parts, the resin glass has a feature in being excellent in impact resistance, lightweight properties, and moldability as compared with the inorganic glass. However, for the resin glass to be used as the alternative of the inorganic glass, problems concerning a linear expansion coefficient, rigidity, strength, flame retardancy are inherent in the resin glass under the current technology, and the resin glass cannot meet performance required for the automotive parts from a viewpoint of passenger protection. Therefore, under the current situation, such a transparent resin material for use in an automobile is limited to application to a small part such as a cover for an automotive lamp represented by a headlamp.
In order to make transparency of the resin and an improvement of mechanical strength thereof compatible with each other, a research on organic/inorganic nanocomposite materials becomes one of solving measures therefor. Representative ones of the research on the organic/inorganic nanocomposite materials include: “Composite Material and Manufacturing Method Thereof” (Japanese Patent No. 2519045) by Toyota Central R&D Labs., Inc.; “Polyamide Composite Material and Manufacturing Method Thereof” (Japanese Patent Examined Publication No. H07-47644 (published in 1995)) by Ube Industries, Ltd. and others; “Polyolefin Composite Material and Manufacturing Method Thereof” (Japanese Patent Unexamined Publication No. H10-30039 (published in 1998)) by Showa Denko K.K.; and the like.
In any of the polymer composites as described above, each of which uses filler on a nano-order level, dispersion of the filler in the resin accounts for a large factor on maintaining the transparency of the resin and improving the properties thereof. For the purpose of enhancing dispersibility of the filler, many various dispersion methods in which selection of microparticles, surface treatment of the particles and optimization of composite synthesis are combined are disclosed. For example, Japanese Patent Examined Publication No. H07-47644 discloses a method of immersing caprolactam as a material of nylon between layers of montmorillonite and polymerizing the caprolactam therewith, thereby obtaining a composite of the nylon and the filler. However, though the improvements of the mechanical properties (strength, elastic modulus, surface hardness and thermal resistance) in the obtained composite are recognized in this method, an application of the method is limited because of insufficiencies of the transparency, hygroscopicity and surface hardness of the composite, and application examples thereof are little.
Meanwhile, in order to make the transparency and the improvements of the properties such as the rigidity and the strengths compatible with each other, the applicant of this application has filed a patent application named “Resin-Made Window and Manufacturing Method Thereof” (Japanese Patent Unexamined Publication No. H11-343349 (published in 1999)). This patent application discloses a resin-made window formed of a transparent resin composition in which microsilica having a diameter of a wavelength of visible light or less is blended into a transparent amorphous organic polymer for the purpose of improving the rigidity, and so on.